Living with the Bay

A regional resiliency plan for Long Island's south shore

2014

The US Department of Housing and Urban Development

Nassau County, NY


Project Team:

Interboro Partners

(Tobias Armborst, Daniel D’Oca, Georgeen Theodore, Pedro Torres, Margaret Zyro, James Gerisi, Riley Gold), Apex, Bosch Slabbers Landscape + Urban Design, Center for Urban Pedagogy, David Rusk, Deltares, H+N+S Landscape Architects, IMG Rebel, NJIT Infrastructure, Planning Program, Palmbout Urban Landscapes, Project Projects, RFA Investments, TU Delft

On Long Island, Superstorm Sandy killed 14 people and damaged close to 100,000 buildings. Nearly 70% of all homes destroyed on Long Island were located in Nassau County, where 35,725 residents were displaced, where a total of 74,736 structures were flooded or destroyed, and where 34,602 cars were damaged or wiped out.


The damage from Sandy was caused primarily by storm surge. But unfortunately storm surge is not Long Island’s only waterrelated threat. Long Island faces serious threats from sea level rise, stormwater, and wastewater. The latter two threats are a major source of pollution: unfiltered stormwater runoff entering the bay by way of the region’s rivers and creeks threatens the bay’s ecology. 

Effluent from the Bay Park Sewage Treatment Plant — which is currently released in the bay — exacerbates nitrogen levels that cause harmful algae blooms, hypoxia, and excessive Ulva seaweed growth and that deteriorate salt marshes that could otherwise help protect Long Islanders from storm surge. The salt marshes are also undermined by overdevelopment, which has increased polluted stormwater runoff and restricted the sediment flow that is essential to the marshes.

And these water-based threats are exacerbated by other threats. For example, New York’s system of “home rule” creates a barrier to the kind of regional decision making that is required to adequately address regional issues that don’t respect municipal lines, even though regional decision making is required to create a built environment that is socially, economically, and environmentally sustainable and just. And while South Nassau County is a great place to live, many of the things that make it great are inaccessible to some people. On the one hand, this is because there is a lack of public access to the region’s natural amenities. On the other hand, it is because parts of the region are unaffordable. Long Island has a vast shortage of apartments and rentals. When Sandy struck, Long Island’s rental vacancy rate was just over 4%: neither displaced residents nor relief workers were able to find suitable temporary housing.


So, how do we ensure that the next big storm won’t be as devastating as Sandy? How do we keep Long Islanders safe in the face of future extreme weather events and sea level rise? And what can we do to improve the water quality and quality of life in southern Nassau County? What can we do to make living with the bay safe, healthy, fun, and accessible to everyone?


These are the questions we address in Living with the Bay, our comprehensive regional resiliency plan for Nassau County’s South Shore. Our goal is to make the communities around the South Shore’s bays more resilient in the face of the above-mentioned threats, but also to strengthen what makes living near the bays great in the first place.

Threats

Because there are multiple threats, there are no “silver bullet” solutions here, no one response that will solve all of Long Island’s water related problems. A surge barrier might protect Long Islanders from storm surge, but it won’t do much to keep us safe from nor’easters and other rain events that routinely fl ood our communities. Withdrawing or retreating from the coast would result in less flood damage, but the South Shore is certainly not going to throw in the towel. And neither should it.


Our plan therefore presents a range of integrated adaptive measures that keep Nassau County residents safe, and add to the economic, ecological, and social quality of the region. These measures include mitigating the damage from storm surge, stormwater runoff, and sea level rise by recovering the sediment system and strategically deploying protective measures like constructed marshes, dikes, and cross-structures along the urbanizededge; managing stormwater in order to mitigate the damages from common rain events as well as improve the water quality in the bay; and expanding housing options in high and dry areas near public transportation.

Storm Surge

The damage from Sandy was caused primarily by storm surge. In Nassau County, over 113,000 buildings are in the range of a category 2 surge.

A total of 74,736 structures in Nassau County were flooded or destroyed by Sandy.

Sea Level Rise

Sea level rise is a Sandy-like storm surge in slow motion – an inexorable, decade-by- decade phenomenon that never creates a sense of immediate crisis. We have chosen a 6-foot SLR as our base standard.

Stormwater

Overdevelopment has lead to an increase of stormwater runoff into Nassau’s rivers and creeks. During heavy rain, the water in these creeks and rivers rise above the level of the outflow pipes, causing major backups at upland storm drains. Stormwater runoff is also a major source of pollution, which directly threatens the quality of the ecological system of the bay.

Wastewater

Presently, the Bay Park Sewage Treatment Plant releases its partially treated effluent into the bay, exacerbating nitrogen levels that cause harmful algae blooms, hypoxia, excessive ulva seaweed growth, and that deteriorate the bays salt marshes. Extending the outflow pipe into the Atlantic Ocean is an essential component of our resiliency-building efforts.

Five Strategies

We have developed an integrated, tri-scalar approach that includes planning and design efforts at the scale of the region, the subregion, and specific sites.


At the scale of the region, we have developed a draft, longrange, comprehensive, regional resiliency plan for southern Nassau County. This plan includes research, planning and design, and the development of decision-making tools that address the interrelationships between the region’s natural and human-made systems.


At the scale of the sub-region, we focused on high-impact areas to develop prototypical resiliency strategies for ocean shores, barrier islands, saltwater marshes, creeks and river estuaries, and highlands, respectively. While this plan zeroes in on a particular ocean shore, barrier island (Long Beach Barrier Island), saltwater marsh (West, Middle, and East Bays), river estuary (Mill River), and highland (Sunrise Highway corridor), eachstrategy is prototypical and broadly applicable to other ocean shores, barrier islands, saltwater marshes, creeks and river estuaries, and uplands in the entire Sandy-affected region.


Further zooming in to these areas, we selected five specific sites — one for each of the five strategies — to develop catalytic projects that are implementable within the short term and can kick-start longterm change.

STRATEGIES FOR THE BARRIER ISLAND:

THE SMART BARRIER

Due to their location and topography, Long Island’s barrier islands are among the region’s most vulnerable zones when it comes to sea level rise and storm surges. The City of Long Beach has some of the highest residential densities in Nassau County and is home to more than its fair share of the region’s critical infrastructure. Long Beach also had some of the highest concentrations of damage during Sandy. Protecting the barrier island’s population and its infrastructure from future storm events is therefore essential.


For Long Beach, we propose protective measures along the bay front to complement the ongoing work by USACE on the ocean side and create a comprehensive protective system. The goal of these measures is to protect residents and also to provide better connections to the water and simultaneously deal with stormwater flooding.


As a Phase One project, we propose a dike landscape and a water retention park to immediately protect the existing critical infrastructure and some of the most vulnerable areas of Long Beach. As in many places, the area that is most vulnerable to flooding is also the area with the highest concentration of socially vulnerable, low-income residents. Most of Long Beach’s public housing residents not only live with the direct threat of fl ooding, but also withthe indirect threat of potential contamination coming from fl ooded infrastructure next door. The protection of the public housing units is a priority.

Section through the Dike Landscape- Towards a Smart Barrier: The dike will protect from 12’ surges. On the bay side, the dike is sloped to create an accessible bayside park and promenade. Located behind the dike on the landside is a retention landscape that will store, clean and replenish storm water.

A new dike landscape on the bay shore of the barrier island will protect residents and critical infrastructure, provide retention areas for storm water, and provide access to the bay.

The Phase 2 project is a protective system for the entire barrier island. The system consists of compartments that can be built incrementally over time and that provide a full protection for a 12’ surge. With each successive compartment the overall strategy can be evaluated and adjusted.

STRATEGIES FOR THE MARSH:

THE ECO-EDGE

Urban development has negatively impacted Nassau County’s wetlands. Over the past 70 years, southern Nassau County’s bay areas have lost a sizable portion of their wetlands. Wetlands—and, in particular, saltwater marshes—play a critical role in buffering coastal communities. Wetland eradication has left Nassau bay communities more vulnerable to storm surge.


In the West, Middle, and East Bays, we propose new marsh islands that reduce wave action, improve the bay ecology, and afford new recreational opportunities. A second component of this strategy is a system of ring levees that would further protect development along the urbanized edge.


As a Phase One project, we propose to build a marsh island and ring levee along the Freeport waterfront.

Birdseye view of the Eco Edge.

A Greener Edge:

The outer road is slightly heightened, increasing the safety for the houses behind it. An open wadi system buffers the rainwater.

Public Space Along The OuterDikes:

The relation and connection betweenthe marshlands and the urban areas can berestored and improved by developing publicspace along the outer dike areas, leading to adiverse and beautiful environment.

Eco Edge Elements

STRATEGIES FOR THE LOWLANDS:

SLOW STREAMS

Today, the north/south rivers that empty into Nassau’s bay are crucial less for their natural or recreational functions and more for their capacity to drain and channel stormwater runoff. This runoff is a major contributor to the pollution of the bay, but it also causes flooding: when the rivers rise above the outflow pipes that channel the stormwater into the bay, as often happens in Nassau County, the pipes back up and cause flooding upland.


Along the north/south tributaries that drain into the South Shore’s bays, we propose green infrastructure improvements to reduce inundations and pollution and also create publicly accessible greenways that connect the South Shore’s communities. Proposed improvements include safety thresholds with sluices, stormwater swales for infiltration and water storage, fish ladders, and “aquaphilic” housing prototypes. We also propose a partial upstream re-infiltration of purified wastewater from the Bay Park Sewage Treatment Plant.


As a Phase One project, we propose to reduce tidal inundations and better manage stormwater in the Mill River watershed by 1) installing a sluice that would reduce surges during storm events and manage stormwater through compartmentalization, 2) making more room for the river by transforming an existing, undeveloped parcel into an attractive, accessible riverfront park that could filter stormwater, and 3) adding stormwater swales to the streets that are adjacent to the river.

Mill River is transformed into a greenblue corridor that both stores and filters water and provides accessible public space and room for new urban developments.

Slow Stream Elements

View of a street swale performing during a rain event and view of the future river park:

STRATEGIES FOR THE UPLANDS:

GREEN CORRIDOR

One of the best things we can do to create more resiliency in the region is to create affordable opportunities for people to live out of harm’s way, and the underdeveloped Sunrise Highway corridor is a great place to do this. With its public transportation options, relative density, and mixture of uses, parts of the Corridor have the potential to be the dense, walkable, mixed-use environment that so many of today’s Long Islanders—including those displaced by Sandy—are looking for. But the Corridor is also high and dry: just beyond the reach of a category 2 surge, a 6-foot sea level rise, and the FEMA flood zone, the Corridor is as close as you can get to the more vulnerable communities of the South Shore while still being safely out of harm’s way.


Our proposed “green corridor” is a reimagining of the Sunrise Highway–LIRR corridor that would seek to do two things. First, we would target “high and dry” areas along the corridor for mixed-use, mixed-income housing within walking distance of select LIRR stations. Second, we propose to green the corridor itself by

1) improving the capacity of the highly impervious corridor to capture stormwater runoff,

2) relieving “choke points” (points when the north/south rivers and streams are channeled into a pipe that goes under Sunrise Highway) by selectively daylighting rivers and streams,

and 3) bundling these green infrastructure improvements with pedestrian and bike safety improvements that would facilitate pedestrian connectivity and reduce automobile use.


As a Phase One project, we propose to implement a “show piece” of the reimagined Sunrise Highway corridor around the Freeport LIRR station.

Section through Green Corridor:

Green Corridor Elements.

The Green Corridor consists of five elements: green infrastructure, a bike path, pedestrian safety improvements, new rental apartments, and strengthened north / west downtown streets.

planning